Increasing requirements for automobiles with lower fuel consumption have recently created demand for a tire having low rolling resistance. To obtain such a tire, a rubber material with low heat generation property has been demanded as a rubber material for tire tread, which is directly in contact with the ground surface. In contrast, such a rubber material for tire tread is required to have excellent breaking performance on wet roads (wet skid resistance) and a fracture strength sufficient for practical use from the viewpoint of safety.
Examples of rubber materials meeting such requirements include a rubber composition with silica as a reinforcing filler for rubber materials. In addition, there exists a rubber composition with a diene-based rubber having a functional group interactive with the surface of silica, and the diene-based rubber provides silica in the rubber composition with satisfactory dispersibility and provides excellent low heat generation property due to its high affinity to the surface of silica.
For example, Patent Literature 1 discloses a modified diene-based rubber obtained through reacting a modifier having a glycidylamino group with a polymer terminal, and Patent Literature 2 discloses a modified diene rubber obtained through reacting a glycidoxyalkoxysilane with a polymer terminal. Patent Literatures 3 and 4 disclose a modified diene rubber obtained through reacting alkoxysilanes containing an amino group with a polymer terminal, and a composition of the diene-based rubber and silica. Moreover, Patent Literature 5 discloses a diene-based rubber obtained through subjecting an active polymer terminal and a polyfunctional silane compound to coupling reaction.